1. Field of the Invention
The present invention relates to a musical information processing terminal for reproducing musical information which is transmitted and received in a musical lesson or the like performed through a communication network, a control method for controlling the musical information processing terminal, and a program for implementing the control method.
2. Description of the Related Art
In a musical classroom where musical lessons are performed through a communication network, there are used a terminal for a teacher which is provided with an electronic musical instrument and a microphone. When a teacher plays the electronic musical instrument, performance data in the MIDI format (MIDI data) is generated by the teacher playing the electronic musical instrument, and when the teacher speak to give comments or musical instructions, his speech is picked up by the microphone to generate audio data. Each time such MIDI data and audio data are generated, the MIDI data and the audio data are transmitted from the terminal for the teacher to a plurality of terminals for students. On the other hand, the plurality of terminals for students are each provided with a reproducing device that reproduces MIDI data and audio data from the electronic musical instrument and the microphone of the terminal for the teacher. The reproducing device reproduces MIDI data and audio data received from the terminal for the teacher in order in which they are received.
In this system, on the side of the terminal for the teacher, the teacher's performance using the electronic musical instrument not only generates MIDI data from the electronic musical instrument but also generates actual sounds of the electronic musical instrument which are input to the microphone. Thus, the actual sounds of the electronic musical instrument are contained in the audio data transmitted from the terminal for the teacher to the terminals for students. However, there occurs a delay in reproduction of the audio data relative to reproduction of the MIDI data due to a difference in transmission time and reproduction processing time between the two kinds of data. Therefore, if the MIDI data and the audio data are reproduced in the order in which they are received, the reproduction sound of the MIDI data and the reproduction sound of the audio data are slightly shifted in timing so that they overlap each other, resulting in overlapping reproduction like round singing.
One way to avoid such shifting is, for example, that the reproduction of the MIDI data is delayed by an amount corresponding to the reproduction delay time of the audio data so as to reproduce the two kinds of data in synchronism with each other. However, such synchronized reproduction is technically difficult to perform, and it is particularly difficult to eliminate the shifting for all the plurality of terminals for students.